The uLisp (Lisp for microcontrollers) website has updated their article on graphical ray tracing with uLisp to include the new, powerful Adafruit Clue board featuring the new nRF52840 processor.

This is a simple ray tracer written in uLisp, running on a colour TFT display. The scene contains five spheres and a plane.

The Adafruit CLUE is an ideal platform for this application. It’s a fast platform for running uLisp, and incorporates a 1.3″ 240×240 colour TFT display (above).

Here’s the full version of the program for the Adafruit CLUE in a single file: Ray tracing program CLUE.

uLisp contains instructions to work with the hardware in the Lisp environment.

You can also see how the code works well on other Adafruit boards like the ItsyBitsy M4 below.

On an Adafruit ItsyBitsy M4 it occupies about 1460 Lisp objects and takes about 230 seconds. It should also run nicely on an Arduino Due or ESP32.

For details of the wiring to the TFT display, and the display interface, see Plotting to a colour TFT display. Alternatively you could modify the program to plot to a different display.

Here’s the full version of the program for a 160×128 colour TFT display in a single file: Ray tracing program.

See the article here and more information about the new CLUE board here.